PCB Factory Automation: Robots on the Production Line Board fabrication and assembly have been automated for decades in the process itself, while the movement of material between those processes remained manual. That is where factory automation is now concentrated, and it is changing how a board shop is laid out,…

Step Stencil Design for Mixed Paste Volumes on a PCB A board rarely needs the same paste volume everywhere. A power component may want a thick deposit for a strong fillet, while a fine pitch package on the same panel needs a thin one to avoid bridging. A single foil…

Heatsinks and Thermal Interface Materials: Selection and Attachment A heatsink is only as good as the interface between it and the component. The interface is a thin layer of material that exists to fill the microscopic gaps between two surfaces that are never as flat as they look, and its…

Solder Paste Abandon Time and Stencil Dwell Control Solder paste begins to change the moment it is spread across a stencil. Solvent leaves the surface, flux absorbs water from the air and the paste stiffens as its structure rebuilds. Abandon time is the industry term for how long paste can…

UART Serial Interface Circuit Design A UART is the simplest way to move data between two devices: one wire each way, no clock, and a frame defined only by the timing of the bits. That simplicity is also its weakness, because both ends must agree on the rate and both…

Traceability Marking: 2D Codes, Serialisation and Read Rate A board that carries a serial number and a two dimensional code can be traced from the panel it was cut from to the customer that received it. The marking is a small part of the cost and the enabler of everything…

PCB Antenna Design: Sizing, Ground And Tuning An antenna printed directly on a circuit board looks like a simple piece of copper, and behaves like something far less predictable. Its performance depends on the board it is printed on, on what surrounds it in the finished product, and on how…

ESD Control on the Assembly Floor: Wrist Straps and Beyond ESD control on an assembly floor is a programme rather than a piece of equipment, and the parts of it that fail are almost never the parts that cost the most money. A wrist strap that is worn but not…

Aqueous Cleaning of Assemblies: Chemistry, Rinse and Drying Cleaning an assembly after soldering is a chemistry problem with a mechanical solution, and the failure mode when it goes wrong is residue left in a place nobody can see. The measurement that settles the question is ionic contamination, and it is…

Ceramic Substrate Or Aluminium: How To Choose When a circuit has to get heat out of a small area, the choice of substrate becomes one of the first decisions rather than one of the last. Aluminium and ceramic boards both solve the problem, but they solve it differently, and the…